What is Focus?

Focus determines where keyboard events go in the page.

Move focus around the page using your keyboard:

• TAB will move focus forward
• SHIFT - TAB will move focus backwards

• Arrow keyscan be used to navigate inside of a component

  https://www.w3.org/TR/html5/editing.html#focus-management

Implicitly focusable

: automatically in tab order + built-in keyboard event handling.